Download 1 - Daniel O`Brien

1. A) Garibaldi Volcanic Belt Map including the Volcanoes of Whistler
This is a map of the Garibaldi Volcanic Belt and Mount Garibaldi area. Mounts Garibaldi,
Cayley and Meager are the three volcanoes in the Whistler area.
Info: http://www.pep.bc.ca/hazard_preparedness/volcano/volcano-hazards-in-bc.pdf
Map: http://upload.wikimedia.org/wikipedia/commons/thumb/e/ee/Garibaldi_Volcanic_Belten.svg/776px-Garibaldi_Volcanic_Belt-en.svg.png
B) The Volcanic Features of Whistler
The Garibaldi Volcanic Belt is a north-south range of volcanoes in southwestern British
Columbia, Canada and it includes the Mounts Cayley, Fee, Garibaldi, Price, Meager, the
Bridge River Cones, and the Squamish Volcanic Field. The formation of the Garibaldi Volcanic
Belt was caused by the subduction of the Juan de Fuca Plate and the Explorer plates under
the North American Plate along the Cascadia subduction zone. It is a 1,094 km-long fault,
which extends 80 km off the west-coast of the Pacific Northwest from northern California to
Vancouver Island, British Columbia. The plates move approximately over 0.4 inches
(10 mm) annually at an adequate oblique angle to the subduction zone. The main areas
of the Garibaldi Volcanic Belt within a 100km radius of Whistler include Mounts Garibaldi,
Cayley and Meager.
http://www.absoluteastronomy.com/topics/Garibaldi_Volcanic_Belt
C) Threat to Whistler under Explosive Eruptions
Mounts Garibaldi and Cayley are the two volcanoes that are the most likely to affect the
community of Whistler if an eruption should occur. Although no Plinian eruptions (with dense
clouds of gas and tephra being propelled upwards for many kilometres) have been identified in
Mount Garibaldi's eruptive history, even Peléan eruptions (avalanches caused by volcanos
consisting of large quantities of gas, dust, ash, and lava) could create large amounts of ash
that could significantly affect Whistler. Ash columns may rise to several hundred meters above
the volcano, posing as a possible threat to Vancouver's air traffic due to its close proximity.
Furthermore, the leftover glacial ice covering the Mount Garibaldi which continues to melt may
cause floods, lahars, or debris flows that might pose as a possible threat to nearby
communities. An eruption creating floods could demolish sections of Highway 99, a road used
for traveling to Whistler, which is already burdened by landslides and debris flows from the
Coast Mountains. Moreover, during the verge of its next eruption, the continued presence of
magma near the surface of Mount Cayley in the future would eventually make contact with
surface water, causing phreatic eruptions and debris flows, which would force Highway 99 to
be closed or require improvement.
Info: http://www.absoluteastronomy.com/topics/Mount_Garibaldi
http://www.absoluteastronomy.com/topics/Mount_Cayley
http://www.absoluteastronomy.com/topics/Whistler,_British_Columbia
Peléan eruption def: http://www.websters-online-dictionary.org/Pe/Pelean+eruption.html
Plinian eruption def: http://www.answers.com/topic/plinian-eruption-1
2. Most Active Volcanic Region and Recent Eruption in Canada
The most active volcanic region in Canada is the Stikine Volcanic Belt (or Northern Cordilleran
Volcanic Province). This massive volcanic region stretches from just north of Prince Rupert,
into the Yukon Territory and the Alaska border, and contains over 100 volcanoes. During the
last few hundred years, 3 of these volcanoes have erupted and 2 of these eruptions were
witnessed by people. This belt includes Mount Edziza, Level Mount, Volcano Mount, and the
young Tseax Cone (240 years), Lava Fork (360 years) and Ruby Mount (103 years). The
formation of these volcanoes resulted in the extensional fracturing of the crust in response to
the Pacific Ocean plate dragging northward along the edge of the North American plate,
towards the Aleution subduction zone. The most recent volcanic eruption in Canada was the
Lava Fork. based on tree-ring-core dating and 14C dating, the youngest lava flow is
approximately 150 years old. Lava Fork is within Canada's most active volcanic region and is
one of 10 volcanoes found along or near the Iskut River. Lava Fork's deposits contain mostly
basaltic lava flows (approximately 22 km long in total), which erupted from a vent high up on
the side of a glaciated, U-shaped valley and streamed 5 km southward, crossing the border
into Alaska, dammed the Blue River, and formed several small lakes. Large trees that were
engulfed by the lava flows currently remain lodged in the top of the flows and can be found in
many areas. Today, the site of the most recent volcanic eruption in Canada is protected by the
Lava Forks Provincial Park.
Info: http://gsc.nrcan.gc.ca/volcanoes/map/index_e.php
http://gsc.nrcan.gc.ca/volcanoes/cat/volcano_e.php?id=svb_lfk_040
http://www.env.gov.bc.ca/bcparks/explore/parkpgs/lava_forks/
3. A) Volcanic Gas Emissions
The most abundant gases usually released into the atmosphere from volcanoes are
carbon dioxide (C02) and sulfur dioxide (S02) which pose the greatest potential hazard to
people, animals, agriculture, and property. The increase in ratios of gas and steam emissions
from fumaroles, mudpots and solfataras often display that the magma is rising closer to the
surface. Obtaining this information is generally challenging as the emissions damage
instruments and are noxious to their observers. Today, volcanologists use so-called "Japanese
boxes" (beakers of potassium hydroxide, a strong and basic solution) routinely, and sometimes
they have to manually assess the beakers. As the highly acidic gases released by the volcano
percolate through holes in a crate covering the beakers, they progressively alter the solution's
composition in months before a large eruption. This helps them in predicting future eruptions.
Info: http://volcanoes.usgs.gov/hazards/gas/index.php
http://www.pbs.org/wgbh/nova/vesuvius/predict.html
http://library.thinkquest.org/17457/volcanoes/prediction.php
B) Volcanologist Lava Sampling
Fresh, hot, lava samples provide important information about the activity within a volcano's
magma chambers. For instance, volcanologists can differ between the magma that has moved
up quickly from deep within the Earth and the magma stored for many years in a shallow
chamber within the volcano. It's important for scientists to get the samples while they're hot
and quickly cool them in cold water to avoid chemical changes that result from the
crystallization during slow cooling. Lava cooled into a solid is called an igneous rock.
Volcanologists also regularly monitor lava temperatures, another indicator, in anticipation of
forecasting major eruptions.
Photo: http://www.scientificamerican.com/article.cfm?id=what-causes-a-volcano-to
Info: http://hvo.wr.usgs.gov/volcanowatch/1997/97_03_14.html
http://www.scientificamerican.com/article.cfm?id=what-causes-a-volcano-to
http://wiki.answers.com/Q/What_makes_lava_turn_into_igneous_rock